This means that the size of a given differential backup depends on the amount of data that has changed since the base. Overview of differential backupsĪ differential backup captures the state of any extents (collections of eight physically contiguous pages) that have changed between when the differential base was created and when the differential backup is created.

Under the full recovery model, using differential backups can reduce the number of log backups that you have to restore. In these cases, differential database backups enable you back up frequently without the overhead of full database backups. Therefore restoring from a differential backup will necessarily take more steps and time than restoring from a full backup because two backup files are required.ĭifferential database backups are especially useful if a subset of a database is modified more frequently than the rest of the database. However, before you restore a differential backup, you must restore its base. This facilitates taking frequent data backups, which decrease the risk of data loss.

A differential backup records only the data that has changed since the full backup upon the differential backup is based. BenefitsĬreating a differential backup can be much faster than creating a full backup. The base backup for a file differential backup can be contained within a full backup, a file backup, or a partial backup. Full backups, except for copy-only backups, can serve as the base for a series of differential backups, including database backups, partial backups, and file backups. The full backup upon which a differential backup is based is known as the base of the differential. A differential backup captures only the data that has changed since that full backup. This backup and restore article is relevant for all SQL Server databases.Ī differential backup is based on the most recent, previous full data backup.

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